The invention relates to a solar polyurethane thermal insulation material which belongs to the technical field of solar thermal insulation materials. MDI (methyl diphenylene diisocyanate) containing 30-32wt% of NCO (isocyanate group) is mixed with full-water combined polyether according to a weight ratio of 1.294:1, thereby acquiring the solar polyurethane thermal insulation material. The full-water combined polyether comprises bio-polyether polyol, deionized water, sorbierite polyether, cane sugar polyether, foam evening agent and catalyst, wherein the molecular weight distribution of the bio-polyether polyol is 1000-1200; a hydroxyl value is 490mgKOH / g; a viscosity at 25 DEG C is 3600mPa.s; the foam evening agent is polyether modified organic siloxane; and the catalyst is N,N-dimethyl cyclohexane. The solar polyurethane thermal insulation material has the advantages that the preparation process is simple, the operation is convenient and the automatic continuous production is realized; the environment is protected, an ODP (Ozone Damaging Potential) value is zero and the toxic side effect does not exist; and the phenomena of contraction, transformation and expansion at normal temperature, 100 DEG C or 25 DEG C are avoided, the size stability is high, the strength is high, the brittleness is small and the heat-conducting coefficient is small.